If you place the green tomatoes on a windowsill or other bright place, most will ripen slowly, but won't have quite the same flavor as vine-ripened.

We usually make "chow-chow" out of our green tomatoes at the end of the season. That's a kind of pickled relish that's usually made out of a variety of vegetables. Ours is mostly green tomatoes, cabbage, carrots, and onions. Goes great on sausages, burgers, etc.